Should be to sell to Shepard if you can because the price is great even though the company will not be sold. let shepard own the stock. You got great value. Probably he will not buy but no downside to the tender.
But if Shepard controls all the B shares he will likely assert that the Mutual should act on behalf of all of shareholders or be silent regards offers for the whole company, so to recommend accepting tender may be a slippery slope for current major domos.